encasing old bricks in new concrete?

This question is regarding the rear entrance to my basement. I have to pour a "step up" which will act as a curb for drainage to prevent water from coming into the basement. Basically, the area will be about 16 Sqft, and about 8" deep. This would turn out to be quite a few bags of concrete.

At the same time, I have a ton of old bricks doing nothing under a crawl space in my deck. I figured why not kill 2 birds with 1 stone and place the bricks in the area, thereby using less concrete.

Right now, I laid out a layer of bricks across the whole area, and a second layer, perpandicular to the first and on top. This leaves about 2-3" of cover for concrete. I was thinking to mix up a batch of concrete and throw it over these bricks, (into the mold I built, of course). Is there anything wrong with this? Should I put concrete over the first layer of bricks before placing the second layer of bricks? Will there be stability problems? The area I was most concerned with is at the "step up", that the weight on the edge (top corner) would cause something to destabilize, and break free. I tried looking this up online, but strangely, couldn't find any information. I will be tiling the whole thing with 12" tiles.

Please let me know if this is ok, I wanted to start this project after work today, thanks!

It's okay to use bricks as fill, but I am guessing that the arrangement you are planning may not be the best. The concrete won't flow around the bricks, and they could move, eventually causing cracking of the stuff above. Normally for a base, you'd pack it down (using something like gravel), but the bricks won't pack, nor are they likely perfectly flat, and would start out with a somewhat unstable (from a tile's viewpoint) base. I think you could get by with one layer, spaced a bit apart so you'd get the concrete to go between them. See what others have to say, as I'm guessing here.

Or, you could essentially 'set' the bricks with some of the concrete acting as mortar, then pour in the rest to fill the form up...that would make it monolithic the full depth rather than a floating layer on a potentially unstable base.